Post lock for chair control



Jan. 14, 1969 F. DOERNER 3,421,727

POST LOCK FOR CHAIR CONTROL Filed May 3, 1966 INVENTOK FRANK 1305mm United States Patent 3,421,727 POST LOCK FOR CHAIR CONTROL Frank Doerner, Waterloo, Ontario, Canada, assignor to Doerner Products Co. Limited, Waterloo, Canada, a

corporation of Ontario, Canada Filed May 3, 1966, Ser. No. 547,715

US. Cl. 248-405 Int. Cl. A47c 3/026; A47c 3/03 3 Claims ABSTRACT OF THE DISCLOSURE Background of the invention For sometime now the chair spindle has been provided with a tapered end which fits into a tapered socket formed in the chair control. It has been found that, in use, the tapered spindle works loose and the chair control shifts its position on the spindle. In assembling the chair control to the spindle, it is desirable to have the control and the spindle maintained in the assembled posi tion at all times having regard to the fact that certain weaknesses in the spindle result in formation of the conventional groove which is cut through the threads.

An illustration of such a structure is to be found in Finn Lie US. Patent 3,027,191 issued Mar. 27, 1962. A self-locking taper is also disclosed in US. Patent 2,424,- 753 to Herold. In that structure Herold secures the post and control in their correct position by staking.

Summary of invention The chair control which is to be used with the present invention may be of the type described in copending applications No. 518,226 filed Jan. 3, 1966 (now Patent 3,278,228), and No. 527,376 filed Feb. 14, 1966, or the above-mentioned Finn Lie. Consequently, only such parts of the chair control as are necessary for explaining the construction and operation of the present invention will be described herein.

The present invention provides a novel structure for removably connecting the chair control spindle to the chair control in a manner that these two parts can be assembled together in a manner that they will not separate under normal operating conditions, will retain their assembled position and can be easily dismantled by a tap on one of the components.

The invention comprises a self-locking taper formed on the upper end of the spindle, a detent formed integrally with and projecting outwardly from said tapered portion, and a spindle socket carried by the frame of the chair control and arranged to receive the tapered end of the spindle, said socket having a longitudinal detent receiving groove in the inner wall thereof whereby when the tapered spindle is fitted into the tapered socket, the detent and keyway mate thereby retain the control and the spindle in their assembled position.

Description of the invention The construction of the present invention will be apparent from the following description, and the accompanying drawings in which:

FIGURE 1 is a fragmentary front view of a swivel- 3,421,727 Patented Jan. 14, 1969 tilting chair which embodies the subject matter of the present invention.

FIGURE 2 is a cross-section upon the line 22 of FIGURE 1 rotated FIGURE 3 is a cross section on the line 33 of FIG- URE 2.

FIGURE 4 is a perspective view of the top end of the chair spindle.

The drawings illustrate a chair having a mobile base 10 which is only shown in part, a chair spindle 11 having a conventional longitudinal groove 19 constructed to embody the present invention, a chair control which is generally indicated by the reference letter A and which will be more particularly described later and a chair seat 12 shown in part.

The chair control A comprises a pair of spiders or arms 13, 14 which are adapted for attachment to the underside of the chair seat 12, a pair of fixed plates 15, 16 carried respectively by the arms 13, 14, and a U frame 17 which is pivotally suspended between and connected to the plates 15, 16 and a bia'sing means generally indicated by the reference 18 yieldably connecting the U frame 17 to the fixed plates 15, 16 and urging said U frame to a stop position relative to the fixed frame and yieldably resisting pivotal movement of the second frame away from said stop position under a force applied by an occupant of the chair. The foregoing is all conventional construction, and forms no part of the present invention, but has been given in a brief manner for the purpose of forming a foundation in explaining the construction and operation of the present invention.

In FIGURE 1, the chair is illustrated with the seat 12 facing frontwards and with the other related parts always facing in the same direction since the control and the spindle always rotate as a unit when the chair is rotated on the base. In this position, the conventional groove 19 of the spindle 11, the purpose of which is fully explained in my said prior application is positioned, when assembled to the control, facing toward one of the sides of the chair seat. In the present installation the groove faces towards the left side of the chair as illustrated in FIGURES l, 2 and 3.

The upper end of the spindle is formed with a selflocking taper (Morse taper) of about 1.5 and with a detent 20 formed integrally on the taper, adjacent the top end, by swaging.

The U frame 17 includes a base portion 21 which has mounted thereon an inverted 'U plate 22 with the legs thereof secured to the base portion 21. The base portion 21 and the U plate 22 are each formed with centrally located spindle receiving sockets 23, 24 respectively, the sleeves being formed by a conventional deep drawing method. The sockets 23, 24 are enclosed within and supported by a supporting collar 25 which is captured between the base portion 21 and the U plate 22. The tapered upper end of the spindle 11 fits into the sockets 23, 24 with a tight locking fit. The sockets 23, 24 are formed with a keyway 26, 26a respectively which receive and engage the detent 20 as shown.

The advantage of this structure is that when the spindle and the control are brought together, the taper will automatically lock these two parts together. There is of course the possibility of discrepancies in the machining of the parts with the result of a slight looseness. The detent 20 which fits into the keyway 26 prevents the spindle coming loose in the chair control and thus prevents accidental disconnection of these parts when the chair is being moved about.

Another important characteristic of the present invention is the positioning of the detent 20 at 90 to the main keyway 19 in the spindle with the main keyway 19 facing laterally relative to the front of the chair. In my copending application, Ser. No. 527,376 filed Feb. 14, 1966, I have described a nylon bushing which is used to mount the spindle in the chair base. If the keyway 19 were to face either to the front or to the rear, relative to the chair, and pressure exerted on the nylon bushing by a backward tilting of the chair, the keyway could damage the nylon bushing, and in fact actually cause failure. By arranging the keyway 19 in the position described in this application, damage to the nylon bushing is avoided.

What I claim as new and desire to protect by Letters Patent of the United States is:

1. In a swivel chair having a base, a rotatable spindle having a conventional threaded portion formed with a longitudinal keyway, a chair seat, a chair control attachable to the chair seat, said chair control having a frame member, means removably securing the upper end of the spindle to the frame member, said means comprising, in combination, a substantially flat base formed as part of the frame member, said base having a centrally located spindle hole with an annular flange therearound forming a first socket; a U-plate supported by the flat base in spaced parallel relationship, said U-plate having a centrally located spindle hole with an annular flange therearound forming a second socket corresponding to and registering with the first socket, said first and second socets having self-locking tapers, a self-locking taper formed on the upper end of the spindle and which fits into the self locking tapers of the sockets, a detent formed integrally with and projecting outwardly from the upper end of said tapered portion, said detent being formed integrally with the upper end of the spindle and longitudinal detent receiving grooves extending the full length of the internal wall of each socket, said grooves being in alignment to each other and parallel to the longitudinal axes of the spindle whereby the tapers on the spindle and the sockets cooperate with the detent and groove as the sole means of retaining the chair control in its assembled position on the spindle.

2. The invention defined according to claim 1 wherein said detent is positioned about circumferentially from said keyway.

3. The invention defined in claim 1 wherein there is provided a supporting sleeve enclosing said sockets, said sleeve being captured between the flat 'base and the base of the U-plate.

References Cited UNITED STATES PATENTS 3,285,639 11/1966 Galla et al. 287-53 526,045 9/1894 Morgan 248-415 908,730 1/1909 Bolens 248-415 1,485,910 3/1924 Dawson 297-305 2,424,753 7/1947 iHerold 297-304 2,463,257 3/1949 Fox 297-301 ROY D. FRAZIER, Primary Examiner.

ROBERT P. SEIITER, Assistant Examiner.

US. Cl. X.R. 

